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1.
Increasing empirical and theoretical evidence supports the idea that sympatric speciation is operating, for example, in species
flocks comprising several closely related fish species within one lake. Divergent natural selection (promoting spatial and
food niche partitioning) and sexual selection (assortative mating) have been identified as key selection factors in intralacustric
adaptive radiations. However, the evolution of social behaviors accompanying such adaptive radiations is less well understood.
Using a phylogenetically young species flock of pupfish (Cyprinodon spp.) as a model, we examined differences among six sympatric species and compared their shoaling, aggressive, and territorial
behaviors with that of a sister species (C. artifrons). Despite an estimated age of the species flock of less than 8,000 years, pronounced behavioral differentiation was found.
C. simus, the smallest species in the flock, shoaled more than the other species and was less aggressive and less territorial than
C. beltrani. F1-hybrids between C. simus males and C. beltrani females showed an intermediate expression of shoaling and aggressive behavior. Niche partitioning among the members of this
species flock appears to be accompanied by rapid divergent evolution of social behaviors. We discuss the potential role of
phenotypic plasticity and within-species variation of social behaviors for such rapid behavioral diversifications in sympatric
speciation processes. 相似文献
2.
Howard H. Whiteman John D. Krenz Raymond D. Semlitsch 《Behavioral ecology and sociobiology》2006,60(1):52-61
The study of reproductive isolation as a prerequisite to sympatric speciation has been limited by the focus on species that
have already experienced such isolation. However, a complete understanding of how such processes evolve depends on observing
taxa before they complete the speciation process. We studied the potential for sexual isolation in the polyphenic mole salamander,
Ambystoma talpoideum, using a series of laboratory and field experiments. This species consists of aquatic paedomorphic adults and terrestrial
metamorphic adults which are exhibited by both sexes and which mate in the same aquatic habitat. Previous field studies on
this species suggested that intermorph breeding would be less common during the winter months, because paedomorphic adults
begin breeding in early autumn and thus may have less energy available for reproduction in the winter. Laboratory experiments
conducted during the winter showed that the mating behavior of paedomorphic males occurred at a much lower frequency than
that of metamorphic males. In contrast, field experiments that best mimicked natural conditions revealed symmetric intermorph
breeding and included multiple paternity shared among males of each morph. This and other studies suggest that there is little
evidence of sexual isolation among morphs based on behavioral interactions alone. However, the potential for partial isolation
still occurs because of temporal and spatial differences in the frequencies of each morph in nature. Our results suggest that
further studies on this system, and other similar polyphenisms, may provide valuable insight into the mechanisms that underlie
the evolution of reproductive isolation. 相似文献
3.
4.
Closely related species provide an interesting and useful model to understand mate communication diversification. Pre-mating
isolation is the result of selection processes and is achieved by utilization of different sex pheromones, but also by different
ecological and life traits such as geographic distribution, host-plant specialization and allochrony of sexual behavior. Here,
we report sex pheromone identifications and pre-mating isolation of two closely related species of stemborers: Busseola segeta and the yet undescribed Busseola nov. sp., developing on different host-plants and in different geographical locations in Kenya. GC–MS analyses showed that the
two species produced the same pheromone components, but in slight different ratios. The respective synthetic pheromone mixtures
tested in the field were attractive for males of each species. The low inter-specific variation in the pheromone mixture would
allow possible interbreeding in case of accidental introduction of both species in the same environment. Under laboratory
conditions, allochrony of the mating period is total and might prevent interbreeding if confirmed in natural conditions. This
point would ensure the reproductive isolation between the two species in case of modifications of ecological factors. This
study and the chemical structures of the identified pheromone components clearly demonstrate that these Busseola species are closely related although they differ in morphology. 相似文献
5.
Parker's seminal work brought attention to the possibility of postmating sexual selection by non-random fertilization success.
Mechanisms for these processes are still only partly understood and there is clearly a need for more studies of intraspecific
variation in sperm precedence. Here, we report results from an experimental study of the variation in fertilization success
between males of the water strider Gerris lacustris. Genital morphology, male body size, and copulation duration were examined as possible correlates of paternity. The significance
of guarding duration was also analysed. Only male genital morphology was correlated to fertilization success. This is one
of the first studies showing a relationship between male genital traits and fertilization success, supporting the view that
sexual selection may be responsible for the rapid and divergent evolution of genital structures in animals with internal fertilization.
The fertilization success of last males varied considerably after double matings with a short mating interval (10 min). Last-male
priority ranged from 0 to 100% and usually one of the males involved fertilized almost all the eggs. After double matings
with a short mating interval, the proportion of eggs fertilized by the last male averaged 0.68 and was greater than 0.5. In
contrast, the average fertilization success was biased towards the first male when the matings were more spread out over time
(24 h). These results do not support earlier suggestions of a widespread last-male sperm priority in water striders.
Received: 28 July 1998 / Received in revised form: 15 March 1999 / Accepted: 28 March 1999 相似文献
6.
A comprehensive understanding of sexual selection requires knowledge of the traits and mechanisms responsible for increasing a male’s paternity share (proportion of progeny sired) relative to that of other males mating with the same female. In this study we manipulated by starvation the expression of traits that might influence male paternity share in Tribolium castaneum. We then conducted experiments to examine how male starvation affects male performance during sequential episodes of sexual selection from mating to progeny production, and investigated female control over specific stages by using live vs dead females. Comparison of starved vs fed males revealed that T. castaneum females have control over spermatophore transfer during mating, as live females rejected inseminations by starved (“low quality”) males. None of the measured male copulatory behaviors (leg-rubbing frequency, asymmetry, and percent of time spent rubbing) affected the probability of successful insemination, but the last two were positively associated with male paternity share. Spermatophore positioning within the female reproductive tract was not affected by male treatment (starved/fed), by female treatment (live/dead), or by male copulatory behaviors. Starvation, however, had a dramatic effect on male reproductive physiology, decreasing both accessory gland size and total number of sperms transferred (but not sperm viability in seminal vesicles). In addition, females who mated to starved males stored fewer sperms in their spermathecae, which, together with decreased ejaculate size, may explain the reduced paternity share of starved males compared to fed males. This study elucidates some cryptic mechanisms influencing male reproductive success and aids our understanding of trait evolution through sexual selection. 相似文献
7.
Chemical signals are important for mate and species recognition. If variation in chemical signals occurs between populations
of the same species, these differences could later preclude mating between populations and lead to speciation. In the Iberian
wall lizard, Podarcis hispanica, the lipophilic fraction of femoral secretions of males is mainly a mix of steroids and fatty acids. Among steroids, the
most abundant compounds are cholesterol and cholesta-5,7-dien-3-ol, which are implicated in intraspecific communication and
sexual selection. Interpopulational differences in chemical signals of males, and in response to these chemicals, could contribute
to reproductive isolation between populations, which would explain the known genetic differences between these populations.
Chemical analyses indicated that five distinct populations of this lizard from Madrid (Central Spain) differed in the proportions
of two steroids (cholesterol and cholesta-5,7-dien-3-ol) in femoral secretions. Moreover, lizards discriminated and had high
chemosensory responses (i.e., high tongue-flick rates) to these steroids, but showed interpopulational differences. Lizards
from populations with cold temperatures and high relative humidity (i.e., northern Madrid) elicited higher responses to these
steroids, whereas the converse occurred for lizards from populations occupying dry and hot habitats (i.e., southern Madrid).
Interestingly, the magnitude of the chemosensory responses to cholesta-5,7-dien-3-ol in each population mirrored the abundance
of this compound in secretions of males of that population. These results suggest that the importance of cholesta-5,7-dien-3-ol
in males’ secretions might be lower for lizards from the southern populations. These differences in the relative importance
of chemical signals could explain reproductive isolation and cryptic speciation between populations of this lizard. 相似文献
8.
Manuela Bartel Stefanie Hartmann Karola Lehmann Kai Postel Humberto Quesada Eva E. R. Philipp Katja Heilmann Burkhard Micheel Heiko Stuckas 《Marine Biology》2012,159(10):2195-2207
Sperm proteins of the marine sessile mussels of the Mytilus edulis species complex are models to investigate reproductive isolation and speciation. This study aimed at identifying sperm proteins and their corresponding genes. This was aided by the use of monoclonal antibodies that preferentially bind to yet unknown sperm molecules. By identifying their target molecules, this approach identified proteins with relevance to Mytilus sperm function. This procedure identified 16 proteins, for example, enkurin, laminin, porin and heat shock proteins. The potential use of these proteins as genetic markers to study reproductive isolation is exemplified by analysing the enkurin locus. Enkurin evolution is driven by purifying selection, the locus displays high levels of intraspecific variation and species-specific alleles group in distinct phylogenetic clusters. These findings characterize enkurin as informative candidate biomarker for analyses of clinal variation and differential introgression in hybrid zones, for example, to understand determinants of reproductive isolation in Baltic Mytilus populations. 相似文献
9.
Vikram K. Iyengar Thomas Castle Sean P. Mullen 《Behavioral ecology and sociobiology》2014,68(2):275-282
Divergence of sexual signals in sympatry can arise as a consequence of (1) interspecific competition for resources, (2) selection against maladaptive hybridization, or (3) as a result of selection to reduce the cost of interspecific aggression; termed agonistic character displacement (ACD). Calopterygid damselflies have emerged as a model system for studying the evolution of divergent sexual signals due to the repeated evolution of sympatric species pairs with fully and partially melanized wings. Damselfly wing patterns function during both courtship and territory defense. However, the relative contributions of natural and sexual selection to phenotypic divergence and enhanced isolation in sympatry remain unclear in many cases. Here, we investigated the hypothesis that interference competition, in the form of increased interspecific male–male aggression, drives the evolution of character displacement in sympatry between two species of North American damselflies, Calopteryx aequabilis and Calopteryx maculata, that show no evidence of ecological divergence or ongoing hybridization. In paired behavioral trials, we found that interspecific male aggression related to territory defense varied between site, species, and as a function of the relative abundance of con- vs. hetero-specific males. Specifically, we found that large-spotted C. aequabilis males received increased intra- and interspecific aggression but that aggression against large-spotted males declined during the middle of the flight season when both species were equally abundant. Based on these results, we suggest that ACD leads to enhanced species recognition, and may be a common outcome of the antagonism between interspecific male–male competition and the countervailing force of intraspecific sexual selection favoring increased wing melanization among territorial damselfly species. 相似文献
10.
In many salmonid species, males exhibit morphological dimorphism associated with alternative mating behaviors. ”Precocious
males” have a small body size with little or no development of sexual characters and adopt sneaking to gain access to females,
while ”migratory males” of large body size and well-developed secondary sexual characters fight. We quantified selection on
precocious male parr of masu salmon (Oncorhynchus masou) under simulated natural conditions to examine the contribution of morphology to sneaking success. In contrast to the prediction
that sneaking behavior favors small body size, we detected selection favoring relatively large body size for sneaking success.
This selection pressure was caused by the dominance hierarchy within parr and may have been facilitated by indifference of
dominant migratory males to parr. Unlike the secondary sexual characters exhibited by migratory male salmon, such as the hooked
snout and humped back, no morphological characters other than body size contributed to the reproductive success of masu salmon
parr. This non-contribution may have been responsible for the lack of development of sexual characters in precocious males.
Received: 15 November 1999 / Accepted: 20 May 2000 相似文献
11.
Parental investment, potential reproductive rates, and mating system in the strawberry dart-poison frog, Dendrobates pumilio 总被引:1,自引:0,他引:1
We studied the effect of relative parental investment on potential reproductive rates (PRRs) to explain sex differences in
selectivity and competition in the dart-poison frog Dendrobates pumilio. We recorded the reproductive behavior of this species in a Costa Rican lowland rainforest for almost 6 months. Females spent
more time on parental care than males, and `time out' estimates suggest that PRRs of males are much higher than than those
of females, rendering females the limiting sex in the mating process. Males defended territories that provide suitable calling
sites, space for courtship and oviposition, and prevent interference by competitors. Male mating success was highly variable,
from 0 to 12 matings, and was significantly correlated with calling activity and average perch height, but was independent
of body size and weight. Estimates of opportunity for sexual selection and variation in male mating success are given. The
mating system is polygamous: males and females mated several times with different mates. Females were more selective than
males and may sample males between matings. The discrepancy in PRRs between the sexes due to differences in parental investment
and the prolonged breeding season is sufficient to explain the observed mating pattern i.e., selective females, high variance
in male mating success, and the considerable opportunity for sexual selection.
Received: 9 June 1998 / Received in revised form: 27 March 1999 / Accepted: 3 April 1999 相似文献
12.
Merrill A. Peterson Susanne Dobler Erica L. Larson Danielle Juárez Tim Schlarbaum Kirsten J. Monsen Wittko Francke 《Chemoecology》2007,17(2):87-96
Summary. Chemical signals frequently underlie sexual isolation between insect species. Our understanding of the evolutionary forces
influencing these signaling systems is known for very few systems, challenging both our efforts to understand insect speciation,
and our ability to predict long-term changes in the chemical communication systems of insects. Thus, we are in need of more
systems in which both the chemical signals causing sexual isolation and the evolutionary forces driving sexual isolation are
understood. Sexual isolation in the hybrid zone between Chrysochus cobaltinus and C. auratus has apparently increased in response to natural selection against hybridisation (i.e. reinforcement). Previous experiments
suggested that this isolation was due, at least in part, to male preferences for conspecific females. Here, we confirm this
role of male choice, and document that male mate choice in this system is influenced by cuticular hydrocarbon (CHC) profiles.
Specifically, male C. cobaltinus responses to control cadavers and conspecific female cadavers painted with different cuticular hexane extracts, together
with analyses of the composition of those extracts, revealed that male mate choice is governed by CHC profiles. Multivariate
analyses of GC profiles demonstrated that those profiles are indeed both sex- and species-specific. Although GC-MS enabled
identification and quantification of the specific cuticular hydrocarbons, we have not yet determined which individual compounds
govern mate choice. Having established that CHCs influence sexual isolation in this system, we can now assess the evolutionary
lability of these cues, which will inform both our understanding of speciation, and of the conditions under which the chemical
signaling systems that influence mate choice in insects can evolve. 相似文献
13.
Tagide N. deCarvalho Daniel J. Fergus Rayna C. Bell Kerry L. Shaw 《Behavioral ecology and sociobiology》2012,66(9):1333-1340
In many organisms, mating behavior occurs at a particular time of day, which may be important for avoiding mate competition or interspecific mating. Crickets of the Hawaiian genus Laupala exhibit an unusually protracted courtship in which males produce a series of nuptial gifts prior to the species-typical time of mating. Mating time is one of several rhythmic behaviors that have diverged among closely related Laupala species, which exhibit an extremely high speciation rate. Mating rhythm may reflect direct selection on male and/or female sexual receptivity or the pleiotropic consequence of selection on other rhythmic behaviors. To examine the role of sexual rhythmicity in Laupala cerasina, we characterized the time boundaries or “circadian gate” of courtship and mating, as well as female phonotactic response to male song. We also examined which sex is responsible for mating rhythmicity by phase-shifting males relative to the female photophase. Our results demonstrate that mating behavior is gated by the end of the light phase. Time limits to female mating receptivity were not observed and thus male rhythm alone appears to be responsible for the timing of mating. Furthermore, when courtship is initiated later in the day, males produce fewer nuptial gifts and increase nuptial gift production rate while delaying mating, suggesting that the number of gifts a female receives is important to male reproductive success. 相似文献
14.
Peter D. Dijkstra Ole Seehausen Boye L. A. Gricar Martine E. Maan Ton G. G. Groothuis 《Behavioral ecology and sociobiology》2006,59(5):704-713
It has been suggested that sympatric speciation can be driven by sexual selection on male mating traits alone. However, a
fundamental problem for this process is the lack of ecological differentiation that would stabilize the coexistence of incipient
species through frequency-dependent selection. Such selection can also occur if male aggression is primarily directed towards
similar rather than towards dissimilar phenotypes, so that rare male phenotypes would enjoy a negatively frequency-dependent
fitness advantage. We experimentally tested such an aggression bias in two recently diverged, ecologically and anatomically
similar sympatric cichlid species pairs of the genus Pundamilia from Lake Victoria. Territorial males of a pair of partially reproductively isolated species with red and blue nuptial coloration,
respectively, studied in the laboratory were confronted simultaneously with both colour types enclosed in transparent tubes.
Red males were more aggressive to red stimuli under white light but not when colour differences were masked under green light.
Blue males were equally aggressive to both stimuli in both light conditions. Males of two apparently fully reproductively
isolated species, again one with red and one with blue nuptial coloration, studied in the field, both directed more aggressive
behaviour towards conspecific than towards heterospecific stimulus males. The differential allocation of aggression would
create an advantage for males of the less abundant phenotype or species, thereby potentially supporting stable coexistence
of the phenotypes. The finding that this effect was less clear in the partially reproductively isolated species pair than
in the fully isolated species pair is discussed. 相似文献
15.
The aim of this study was to investigate reproductive strategies and their consequences in gray mouse lemurs (Microcebus murinus), small solitary nocturnal primates endemic to Madagascar. Previous reports of sexual dimorphism in favor of males and females,
respectively, a high potential for sperm competition and pheromonal suppression of mating activity among captive males, led
us to investigate mechanisms of intrasexual competition in a wild population. Based on 3 years of mark-recapture data, we
demonstrate that sexual dimorphism in this species fluctuated annually as a result of independent changes in male and female
body mass. Male body mass increased significantly prior to the short annual mating season. Because their testes increased
by 100% in the same period and because their canines are not larger than those of females, we suggest that large male size
may be advantageous in searching for estrous females and in enabling them to sustain periods of short-term torpor. In contrast
to reports from captive colonies, we found no evidence for two morphologically distinct classes of males. Finally, we also
show that most adult males are active throughout the cool dry season that precedes the mating season, whereas most adult females
hibernate for several months. This is in contrast to other solitary hibernating mammals, where males typically emerge 1–2
weeks before females. Thus, this first extended field study of M.␣murinus clarified previous conflicting reports on sexual dimorphism and male reproductive strategies in this primitive primate by
showing that their apparent deviation from predictions of sexual selection theory is brought about by specific environmental
conditions which result in sex-specific life history tactics not previously described for mammals. A general conclusion is
that sexual selection can operate more strongly on males without resulting in sexual dimorphism because of independent selection
on the same traits in females.
Received: 6 July 1997 / Accepted after revision: 28 March 1998 相似文献
16.
Panu Välimäki Sami M. Kivelä Maarit I. Mäenpää 《Behavioral ecology and sociobiology》2011,65(11):2037-2047
Inbreeding depression is a relative decline in fitness in offspring of related parents. The magnitude of inbreeding costs
varies among taxa and may increase under stressful conditions. Inbreeding tolerance is expected to be low and selection for
inbreeding avoidance intense when both sexes invest substantially in shared offspring like in nuptial gift-giving butterflies.
This is especially true for increasing mating rate for inbreeding avoidance as nuptial feeding decreases net costs of mating
for females. We explored implications of inbreeding in the nuptial gift-giving green-veined white butterfly, Pieris napi. Compared to outbred ones, partially inbred (F = 0.25) eggs and neonate larvae had 25% lower hatching success and 30% lower survival until adult eclosion, respectively.
Inbreeding was also associated with small size. Yet, the magnitude of inbreeding depression was independent of larval conditions.
A lack of assortative mating and mating durations independent of mating type suggest that neither females nor males discriminate
close relatives (r = 0.5) as mates. Indicative of a postcopulatory mechanism to avoid inbreeding, female remating intervals decreased following
incestuous matings. Such a plastic response may affect the level of postcopulatory sexual selection as female remating interval
(time between successive matings) is necessarily negatively correlated with mating rate (matings per unit time) and mating
frequency (lifetime number of matings), and precopulatory mate choice appeared insignificant. Moreover, incest-induced shift
in the phenotype towards the adaptive peak may contribute to the evolution of female mating rates, although alternative explanations
for polyandry besides material benefits have rarely been invoked when nuptial feeding is involved. 相似文献
17.
Gabrielle A. Archard Innes C. Cuthill Julian C. Partridge 《Behavioral ecology and sociobiology》2009,64(2):169-182
Male guppies, Poecilia reticulata, have color patterns that result from a balance between natural selection for crypsis to avoid predators and sexual selection
for bright, complex patterns that attract females. Males use displays to show off these patterns to potential mates, but their
conspicuousness also depends on the light environment in which they are viewed. We investigated variation in natural underwater
guppy light environments in Trinidad, West Indies, and found that mating behavior is correlated with both the ‘quantity’ (total
irradiance) and ‘quality’ (spectral composition) of light: light intensity and the proportion of ultraviolet light were negatively
related to display rates. Experimental manipulation of light environment to mimic natural daily changes demonstrated that
these relationships are causal and are independent of time of day effects. At lower light levels, when guppies are less detectable
by visually hunting predators, females had more opportunity for active mate choice, because males displayed more. However,
these light conditions may reduce the ability of females to accurately discriminate between males. Guppy mating behavior is
therefore strongly affected by light environment, and this may have important effects on sexual selection. 相似文献
18.
Protandry, the earlier arrival of males than females to breeding areas, is widespread in birds, but its underlying mechanisms
are far from well understood. The two, not mutually exclusive most highly supported hypotheses to explain avian protandry
postulate that it has evolved from intrasexual male competition to acquire the best territories (“rank advantage” hypothesis)
and/or to maximize the number of mates (“mate opportunity” hypothesis). We studied for two consecutive years the relative
importance of both hypotheses in a population of pied flycatchers (Ficedula hypoleuca), a territorial songbird with a mixed mating strategy. We measured territory quality using a long-term dataset on nest occupation
and breeding output, and we used molecular techniques to assess male fitness across the range of social and genetic mating
options. Territory quality was unrelated to breeding date and had no influence on extra-pair paternity or social polygynous
events. However, males breeding early increased their chances of becoming socially polygynous and/or of attaining extra-pair
paternity and, as a consequence, increased their total reproductive success. These results support the “mate opportunity”
hypothesis, suggesting that sexual selection is the main mechanism driving protandry in this population. 相似文献
19.
Opportunity and recognition isolation can lead directly to reproductive isolation, the former via divergence in the location
and timing of breeding, and the latter via differential mate preferences. We describe the potential significance of these
factors in the maintenance of reproductive isolation in a clade of triplefin fishes that occur sympatrically around coastal
New Zealand. Specifically, we investigate the roles of spawning time and nesting habitat in promoting opportunity isolation,
and of interspecific variation in male body length and breeding colouration in promoting recognition isolation. The triplefin
species investigated are reproductively active over several months and show high overlap in breeding times, thus rejecting
temporal isolation as a mechanism. Differences in nesting habitats resulted in a reduced probability of encounter between
some species, especially between sister-species pairs. Interspecific colour differences generally decreased during the reproductive
period, and males of sister-species pairs showed no interspecific colour differences in the ultraviolet light spectrum, thus
mate selection based on male colour patterns is unlikely to lead to premating isolation. Finally, males of closely related
triplefin species differed in body length, a secondary sexual trait often involved in assortative mating. Thus, spatial differences
in nesting habitats reduce the chances of encountering allospecific mates, which may facilitate opportunity isolation and
differences in male length, possibly related to species-specific female selection on male body size, may lead to recognition
isolation. The combination of limited spatial overlap in nesting habitat and differences in male body size may facilitate
species assortative mating in sympatry or parapatry. 相似文献
20.
Katleen Huyghe Raoul Van Damme Karin Breugelmans Anthony Herrel Bieke Vanhooydonck Zoran Tadič Thierry Backeljau 《Behavioral ecology and sociobiology》2014,68(8):1357-1366
Although laboratory measurements of whole-animal performance have become a standard tool in evolutionary biology, if and how interindividual variation in performance translates into differential fitness remains poorly understood. Particularly rare are studies that have connected performance to mating and reproductive success in the field. In this study, we use DNA microsatellite parentage analyses to study the fitness gradient in a colour-polymorphic lizard, Podarcis melisellensis. We report on two surprising findings. First, contrary to our expectations, individual sprint speed and bite force capacity correlated negatively, not positively, with male mating and reproductive success. Second, we found an unexpected degree of promiscuity in females. Also, contrary to traditional parental investment theory, the variation in mating success and reproductive success was as high in females as in males. Our results call for a better integration of whole-animal performance and life history traits, and for a reconsideration of the ideas on the likeliness of sexual selection acting on female phenotypes. 相似文献